Device packages act as a heat sink to draw heat away from devices housed by the package, and provide a means for interfacing devices to a circuit board or other system. Heat sinking lowers the operating temperature of the devices, generally improving reliability and increasing the MTBF (mean time before failure) of the devices, as the MTBF generally increases as operating temperature is lowered.
In the known device package 10 shown in FIG. 1, a device 12 is mounted on a heat sink 14 that is embedded in a plastic body 16. The plastic body provides structural support for conductive leads 18 that interface the device to a circuit board external to the device package. As the plastic body is an insulator, heat conduction through the plastic body 16 is generally very poor. Furthermore, the plastic body increases the footprint X1 of the device package 10 beyond the footprint X2 of the heat sink, causing the device package to be larger than the heat sink. As a result, in this type of device package, the device does not benefit from reduced operating temperatures that would result were the heat sink to occupy the full footprint of the device package.
A device package constructed according to the embodiments of the present invention has a conductive substrate with at least one mounting site on a top-side, and an insulating substrate with a first side on the top side of the conductive substrate. The insulating substrate has at least one aperture providing access between a second side of the insulating substrate and the one or more mounting sites. The second side of the insulating substrate has one or more signal paths that couple the one or more apertures to contact sites disposed about the insulating substrate. Conductive tabs are coupled to corresponding contact sites.